Jupiter is the fifth planet from the Sun and the largest in the Solar System. Jupiter is more than twice as massive as all the other planets combined.

Jupiter is the Roman name of Zeus, the king of gods, the ruler of Olympus. Jupiter was known to astronomers in ancient times as it is the fourth brightest object in the sky (after the Sun, the Moon and Venus).

Jupiter has at least 67 moons, the larger ones were discovered by Galileo Galilei in 1610 (Io, Europa, Ganymede, Callisto). Some of the more recently discovered are Metis, Adrastea, Amalthea and Thebe, Leda, Himalia, Lysithea, Elara, Ananke, Carme, Pasiphae and Sinope.